Alloy



Patented Apr. 13, 1926.

UNITED STATES 1 1,580,662 PATENT OFFICE.

PIERRE GIRIN, OF PARIS, FRANCE, ASSIGNOR T SOCIETE ANONYME DE COMMENTRY FOURCHAMBAULT & DECAZEVILLE, 0F PARIS, SEINE, FRANCE.

ALLOY.

No Drawing.

T 0 all whom it may concern:

Be it known that I, PIERRE GIRIN, a citizen of the Republic of France, residing in Paris, Department of the Seine, France,

have invented. a certain new and useful Alloy, of which the following is a specification.

It has long been known that the brittleness of ordinary and special steels increases very rapidly as the temperature falls below the ordinary temperature. Thus during very severe winters there is an increase in the number of accidental breakages of railway rails and carriage axles.

When the extreme temperatures of liquefied permanent gases are attained, iron and steel are very brittle and break at the least shock, like glass. 1

This property of iron and steel hasfor long been a serious obstacle in the construction of machines required to operate at very low temperatures, so that parts more particularly concerned in the running of the machine are liable to be broken by shocks more or less violent. This is particularly the case in machines for liquefying air by reversible expansion with external work (the Claude system) in this case the valves of the motor in which the expansion occurs should be devoid of brittleness at the Working temperature, which may be below 180 centigrade.

The present invention relates to an alloy of iron, nickel and manganese, which may contain carbon, chromium, copper, cobalt, titanium or vanadium, which alloy at the lowest temperatures (even at 200 centigrade) is completely devoid of brittleness, while at the same time it has a high elastic 40 limit and mechanical strength.

One may take as an example an alloy containing nickel 40-70 per cent, manganese 0.85 per cent, iron the rest.

An example of a definite alloy having a composition between these limits is one containing Ni 55 per cent, Mn 2 per cent, Fe 43 per cent.

Without inconvenience from the point of view of brittleness and for the purpose of 5 realizing some particular accessory quality relating, for instance, to dilatation, electrical properties, or elastic or mechanical properties, the content of nickel or manganese may be varied between the limits indicatedr For example, an alloy containing Application filed April 16, 1919. Serial No. 290,600.

Ni 58, Mn 2, Fe has the expansion of iron, and one containing Ni 46, Mn 1, Fe 53 an expansion equal to'that of ordinary glass.

Thetensile strength and the modulus of elasticlty of an alloy having a certain composition may be brought to any value desired between certain limits. Thus there may be introduced one or several additional elements :-carbon up to l per cent, chromium up to 5 per cent, copper up to 10 per cent, cobalt up to 10 per cent, so: that the field of physical and mechanical constants may be still further enlarged.

Moreover, the addition of 0.2-1 per cent of vanadium, 0.1 to 0.5 per cent of titanium has a very favourable action on the quality of the alloy and the facility with which it can be made. The amounts indicated for the additional elements are substituted for the corresponding amounts of iron.

Such an alloy has all the satisfactory. mechanical properties of reversible ferro nickel and the composition of it renders possible any irreversible transformation and any alteration due to the action of cold. At the boiling point of nitrogen, namely 195 0., the elastic limit may vary between 35 and kilos per square millimeter and the tensile strength between 65 to 75 per square millimeter.

The resilience, measured on the Frmont system, attains kilos at ordinary temperature and preserves this value up to 195 C. For the purpose bf comparison it may be added that the softest iron exhibits at this low temperature only 1-2 kilos.

This new alloy is non-oxidizable and is practically unattacked by sulphuric acid of all concentrations: for example, cold sulphuric acid of 28 Baum dissolves .2m/mg per cm of the alloy, in 6 hours. If desired it may be given the coefficient of expansion of cast iron or steel so that an exact adjustment made at ordinary temperature between two parts,'one of the present alloy andfthe other of iron or steel is maintained the liquefaction of gases which retains its resiliency and mechanical strength at the low temperatures realized in the liquefaction of gases, composed of a nickel-ferrous alloy comprising 40 to 70% of nickel, 0.8 to 5% of manganese, and the principal portion of the remainder of iron.

2. An article of manufacture which retains its resiliency and mechanical strength at industrially low temperatures such as are 10 realized in the liquefaction of gases, composed of a. nickel-ferrous alloy comprising 40 to 70% of niokel,-0.8 to 5% of manganese, and the rest of iron.

In witness whereof, I have hereunto l5 signed my name.

, PIERRE GIRIN. 

